When installing ActiveState Perl in Windows, unless you have IIS installed, it won't modify the PATHEXT variable (to let you run Perl Scripts without the '.pl' extension).

After doing it by hand for a few years (Control Panel > System > Advanced > Environment Variables and edit the System Variable "PATHEXT"), I wrote this script to do it automatically.

Some day I'd like to automate the process of installing all the software I commonly use in Windows, for a new machine (or a VM); if I ever do, this is something I'll run immediately after installing Perl.